Quick closure mechanism for the air passage openings of shelters and the like



3,301,168 NISM FOR THE AIR PASSAGE OPENIN GS OF 5811- 1967 G. SCHINDLER ETAL QUICK CLOSURE MECHA SHELTERS AND THE LIKE Filed April 15, 1964 2 Sheets-Sheet 1 4661 [N VENTORS: 665N321 it! 'IMALEK 8! Jan. 31, 1967 G. SCH!NDLER ETAL 3,301,163

QUICK CLOSURE MECHANISM FOR THE AIR PASSAGE OPENINGS OF SHELTERS AND THE LIKE Filed April 13, 1964 2 Sheets-Sheet 2 [NVENTORS Qdbk aid st'n'nlJLER & B y KMJ- Swine.

A TTORNEY United States Patent Ofifie 3,30 l,l68 Patented Jan. 31, 1967 3,301,168 QUICK CLOSURE MECHANISM FOR THE AIR PASSAGE OPENWGS F SHELTERS AND THE LIKE Gottfried Schindler, Zurich, and Karl Sauter, Uitikon, Zurich, Switzerland, assignors to Luwa Ag., Zurich, Switzerland, a corporation of Switzerland Filed Apr. 13, 1964, Ser. No. 359,394 Claims priority, application Switzerland, Apr. 18, 1963, 4,855/63 Claims. (Cl. 98119) The present invention relates to a quick closure mechanism or device arranged at the air passage openings of shelters or similar structures.

Such quick closure mechanisms should guarantee for a sufficiently rapid and effective sealing of the air passage openings of shelters of all types, especially those which should furnish an increased protective action such as command posts, alarm centers, sanitation stations, etc., in order to screen the shelter against air pressure waves resulting from explosions.

It should be appreciated that particularly high requirements must be placed upon such devices. Thus, on the one hand, they must exhibit an air resistance which is as small as possible during the ventilation operation, that is possess relatively large free openings, and, on the other hand, during impingement of pressure waves must be able to close automatically and quicklythat is in some fractions of a secondand at the same time must be able to absorb considerable pressure surges without damage.

Valve mechanisms have already been proposed to the art for the closure of the air through passage openings in which an axially displaceable guide rod is mounted in a cylindrical ventilation or aeration opening and which carries at its ends a respective mushroom-shaped closure or cover member. In the normal position both closure members are located under spring action at the same spacing from the inlet and outlet mouth of the cylindrical ventilation opening or duct, and indeed such that, for the throughflowing air a similar dimensioned cross-section is available between closure member and the relevant mouth as such itself is exhibited by the cylindrical ventilation opening.

However, such valve mechanisms require a relatively large closure path, acting unfavorably upon the closure time as well as effecting a large terminal velocity of the cover plate-particularly in consideration of the relatively large moved massesas well as a large impact energy upon the edge of the ventilation opening. According to a different construction wherein a valve is installed within a tube member there is indeed achieved good clos ure times, but there results a bad effect upon the available wall surface as well as high manufacturing costs.

Additionally, ball or globe valves have been proposed which are relatively favorable with regard to flow resistance, yet like the previously mentioned plate valves also exhibit a relatively large closure movement or path. In addition, it is difiicult to maintain the weight of the balls small without them becoming deformed upon impact with the valve seat.

Finally, due to the provision of additional bafile plates at the ventilation members there can be achieved that penetration of the peak of the shock-wave is somewhat broken-up and the operation also improved with unfavorable closure times. Systems of this type, however, increase resistance for the air flow during ventilation, are complicated and expensive, and possibly increase the masses to be moved.

The present invention therefore has for one of its primary objects to overcome the disadvantages of the heretofore known devices of the mentioned type and to provide a quick closure mechanism which satisfies the demands and operating requirements placed upon them.

It is, therefore, a further very important object of the present invention to provide a quick closure mechanism for a ventilation system, particularly for shelters, which is very reliable in operation, extremely fast acting, relatively simple in construction, economical to manufacture, and capable of withstanding in an effective manner the shock or suction waves to which the mechanism may be subjected during operation.

The inventive quick closure mechanism is generally characterized by the features that a closure member and a seat or seating portion are constructed as plate-shaped members provided with openings. These members in the closed position bear against one another, whereby the openings of the closure member are displaced or offset with respect to those of the seat portion. Consequently, in the closed position the openings of the closure member lie over the full or uninterrupted plate portions of the seat portion.

By means of this physical structure it is now possible, on the one hand, to optimumly employ the air passage opening for the throughflow of air during normal ventilation operation by the provision of suitable openings or interruptions at the plates and, on the other hand, to maintain at a small value the mass to be moved and the closure path, whereby in the presence of a change of the air pressure which exceeds a given magnitude the ventilation opening is closed within the smallest possible time. It is to be distinctly understood that quick closure mechanisms of this type are not limited in application to circular aeration or ventilation openings or ducts, rather can be advantageously employed with quadrilateral or rectangular openings, so that a given wall surface can be utilized to the best possible extent by honeycombed joining together of such units. The inventive concepts can be easily developed in such a manner that the explosion wave as well as the subsequent suction wave effective in the opposite direction can effect a quick closing of the ventilation openings. Such quick closure mechanisms designed in accordance with the teachings of the present invention can be manufactured at a very favorable cost in comparison with heretofore known devices.

Other features, objects and advantages of the invention will become apparent by reference to the following detailed description and drawings in which:

FIGURE 1 is a fragmentary front view of a quick closure mechanism designed according to the present invention as viewed from the shelter interior;

FIGURE 2 is a cross-sectional view of the quick closure mechanism depicted in FIGURE 1, taken along the line IIII thereof;

FIGURE 3 is a cross-sectional view of the quick closure mechanism depicted in FIGURE 1, taken along the line IIIIII thereof;

FIGURE 4 is a cross-sectional view, similar to FIG- URE 2, of a modified form of quick closure mechanism;

FIGURE 5 is a cross-sectional view of the mechanism depicted in FIGURE 4, taken along the line VV thereof;

FIGURE 6 is an enlarged cross-sectional view showing details of a portion of the quick closure mechanism of FIGURE 5;

FIGURE 7 is a fragmentary front view of a further embodiment of quick closure mechanism designed according to the teachings of the present invention;

FIGURE 8 is a fragmentary front view of a further embodiment of quick closure mechanism designed according to the present invention;

FIGURE 9 is a cross-sectional view of the mechanism depicted in FIGURE 8, taken along the line IX-DC thereof; and

forming an air passage or opening 8b for a shelter. frame portions 2b extend towards one side past the frame slots 17.

FIGURE 10 is a fragmentary perspective view of a portion of the quick closure mechanism depicted in FIG- URES 8 and 9.

Describing now the drawings and with attention initially directed to the embodiment of FIGURES l-3, it Will be seen that an inner frame 2 composed of the frame portions 2a and 2b is inserted in a wall section 1 possessing for instance quadrilateral or rectangular cross-section ad portions 2a and provide two lateral or sidewise boundaries for the air passage. Furthermore, an intermediate frame 3 spaced from the inner frame 2 is arranged in the wall section 1 and at which joins an outer frame 8 provided with a smaller through passage opening 8a in comparison with the intermediate frame 3.

Inserted between the frame portions 2a of the frame 2 and the frame 3 and across the entire width of the wall opening 8b are sealing elements 7, and mounted upon such are flat bars 4. The flat bars 4 can advantageously exhibit a wedge-shaped taper in order to be able to more effectively seal the spacing between the frames 2 and 3. These flat bars 4 partially extend into the opening surrounded by the aforesaid frames and serve as a stop for a seating ,portion or seating element 5 connected by means of screws 6 or similar expedients with such flat bars 4. This arrangement of the flat bars 4 and the base plate or seating element 5 renders it possible to assemble and disassemble the latter from the side of the inner compartment J. The side or face of the seating portion 5 situated opposite the flat bars 4 bears against stop means 21 rigidly connected with the frame portions 2b.

A displaceably arranged cover or closure plate bears against shoulders 9 formed by the outer frame 8, closure plate 10 being movable against the force of springs 11 in the direction of the seating portion 5. These springs 11 hear at one end against this closure plate 10 whereas their other ends are seated upon the floor of suitable recesses 12 provided in the seating portion 5.

Moreover, seating portion 5 is provided throughout its entire surface with divided elongated slots 14 closed at the marginal or peripheral sides 14 and by means of which webs or legs 13 are spaced from one another. The

. Webs 13 can be connected with one another through the agency of crossbars or t-russing spaced from the border or periphery 14. The closure plate 10 is constructed in a manner similar to the seating portion 5, and in this case webs or flanges 16 are spaced from one another by The webs 16 in the present instance are arranged and constructed such that when the closure plate 10 contacts the seating portion 5 they completely cover the slots 14 of the aforesaid seating portion.

During normal ventilation of the installation the closure plate- 10 assumes the position illustrated in the drawings, .with the air entrance being schematically indicated by arrow 18. When a pressure wave occurs in the direction of arrow 18 such initially impinges against the closure plate 10, whereby the latter is displaced towards the seating portion 5 against the force of the springs 11, this taking place with a large velocity. In order to guarantee for complete bearing of the closure plate 10 against the seating portion 5 and thereby a complete covering of the slots 14 of such seating portion 5 the recesses or depressions 12 accommodating springs 11 are sufiiciently configured and dimensioned in order to completely receive these springs 11 when in compressed condition.

Quite obviously, the webs 13 of the seating portion 5 should be so strongly dimensioned that, on the one hand, they are capable of absorbing the impact force of the closure plate 10 and, on the other hand, the peak pressure of an occurring pressure wave Without damage due to fissures, rupture or deformation. On the other hand, the strength or thickness of the webs 16 of the closure plate 10 can be much smaller. These webs 16 are dimensioned such that they will not rupture upon impact of closure plate 10 with seating portion 5. In contradistinction thereto, under certain circumstances it may be desirable that momentary elastic deformation of these webs occur during impact against the seating portion 5 or during appearance of the peak pressure, since by means of the deformation energy a portion of the impact energy and/or the pressure energy of the pressure Wave is destroyed.

The small span of the closure plate 10 resulting from the distribution of the total throughpassages into relatively small air slots bounded by the frame 8 additionally renders it possible to provide a relatively small thickness dimension for the closure plate 10. Consequently, the closure plate 10 also exhibits a relatively small mass which is to be accelerated, thereby permitting a correspondingly large closure velocity. Naturally, the closure velocity is also dependent upon the closure path. Due to the distribution of the total air throughpassage crosssection into numerous small passages it is suflicient to maintain at a small value the spacing between the plates 5 and 10 in the illustrated rest position, that is during normal ventilation, without hereby considerably impairing the passage of air.

The described embodiment of quick closure mechanism or device permits closure times of less than one-hundredths of a second. Indeed, with such small closure times a certain portion of the pressure wave also arrives in the inner compartment I through the throughpassage closure mechanism; however, such pressure surge or pulse is diminished upon passage to such a degree by means of the slots 17 and 14 in the plates 10 and 5, respectively, that for example a filter device arranged in an expansion compartment following the air pass-age openings can no longer be damaged.

It is here to be mentioned that the closure plate 10 must be guided in the intermediate frame 3 in such a manner that it does not tend to tilt or bind even with unequal pressure loading by the pressure wave. The base plate or seating portion 5, on the other hand, is effectively supported against the frame 2 by means of the flat bars 4. The screws 6 essentially only serve the purpose of ensuring that the flat bars 4 can not automatically fall out of their support. Furthermore, it is readily possible to similarly construct all four frame sides of each frame and to arrange the stop means 21 as well as also the flat bars 4 at all sides of the passage 8b. Such is effected, above all, if the recesses in the plates 5 and 10 are not slot-shaped, rather for example comprise a plurality of circular openings, as such will .be described hereinafter.

The variant embodiment depicted in FIGURES 4, 5 and 6 basically difiers from the previously described embodiment in that, in this instance, a second movable seat- I 26. This plate member 25 exhibits slots 27 and Webs 28 situated opposite the slots 14:: and the Webs 13a of the seating portion 5a. A closure plate ltla is arranged intermediate plate member 25 and seating portion 5a which in the rest position is parall'elly spaced from both such plate member 25 and seating portion 5a. This closure plate 10a is supported by the plate member 25 and the seating plate 5a through the agency of springs 11a, similar to the arrangement described in the discussion of the first embodiment. Naturally, when the three plates impact one another the webs or legs 16a of the closure plate Illa obturate the openings in both of the other plates 25 and 5121.

Upon appearance of a pressure wave in the direction of the arrow 29 such initially impinges upon the outer movable seat plate member 25, whereby a portion of the air pulse is propagated through the slots 27 and impinges upon the webs or legs 16a of the closure plate a. This closure plate 10a is thereby moved with a large velocity against the seating plate 5a, whereby its slots or openings 14a, as was the case with the first embodiment, are covered by the webs or legs 16a of the closure plate 10:: and thereby obturated. The remaining components of the air pulse, on the other hand, impinge against the webs or legs 28 of the outer plate and effects that such is likewise placed into motion against the force of the springs 11a, whereby such comes to bear in the terminal position against the closure plate 10a which during this time has already moved forwardly up to the seating portion 5a.

On the other hand, the suction wave is intercepted by the pair of plates 25 and 10a. After fading out of the pressure wave the external movable seating plate 25 and the closure plate 1011 again return to their starting position under the action of the springs 11a. The subsequent suction wave in a direction opposite to the pressure wave i.e. the shock wave impinges upon the seating portion 5a, works its way through the slots 14a against the closure plate 10a and presses the same against the seating plate 25, whereby the slots 27 thereof are closed by the webs 16a and the suction wave is no longer able to travel further.

Since, as previously mentioned, the movable seating plate 25, on the one hand, is only impinged by partial components of the pressure wave, and, on the other hand, however, the suction Wave is considerably weaker than the pressure wave, the webs, or legs 28 of the seating plate 25 can be maintained considerably thinner than those of the seating portion 5a without being subjected to permanent deformation. The reduced dimension of the plate 25 in accordance with the possible suction wave, however, also reduces the mass to be moved, whereby the course of movement can be considerably accelerated.

In FIGURE 6 the air paths during ventilation of the installation are indicated by the arrows 30a. With a pressure pulse the closing-air stream in the direction of the arrow 31a and flowing through the slots 27 of the outer movable seating plate 25 is directed with large force against the webs 16a of the closure plate 10a. During the suction flow, corresponding to arrow 32a, the directed air stream from the opposite direction moves through the slots 14a of the seating plate 5a and impinge against the Webs or legs 16a of the closure plate 10a, in order to force the latter against the outer or external movable seating plate 25.

As previously indicated and according to FIGURE 7, in place of the described slots a plurality of circular openings 33a are provided in the plates. The openings and webs respectively can, however, for example exhibit a quadratic configuration; in so doing it is sought to achieve as large as possible total cross-section of the openings in relation to the web portions. It should be understood that the replacement of the slots with individual openings can be applied in any of the embodiments herein described.

Advantageously, a tough material is employed for the closure plate which-within economic limits combines low weight with large strength, such as thin sheet steel for example. At any rate, during impact of the closure plate with the seating portion it must be prevented that pieces are punched-out or knocked-off the aforesaid closure plate. For this reason the smallest span of the openings is held as small as possible.

This is also of advantage in maintaining the spacing between closure plate and seating portion small, therewith also the closure path, approximately in the magnitude of 1 to 2 centimeters. Furthermore, the plate surfaces destined to bear against one another can be coated with a preferably noncombustible damping material in order to at least partially dampen the impact. Quite obviously, in place of the springs 11 and 11a it is naturally possible to employ other elastic elements or compressible mediums.

It is also conceivable to arrange the movable plates such that in consequence of their own weight they remain in the normal position or return thereto.

The closing time can still be favorably influenced in that, at the locations of the full or uninterrupted portions of the closure member at which impinges the air currents of the explosion wave moving through the openings of the further seating plate there are provided projections or protrusions, indicated in phantom lines in FIGURE 6 by reference numeral 50 at plate member 10a, such projections 5t extending into the openings 14a of seating portion 5a moreover, a similar effect can be reached if closure member 10:: is configured somewhat undulated.

Such described quick closing devices can be installed in groups at a small spacing in suitable walls or other separating and protective members. Since they advantageously can be constructed rectangular, it is possible to achieve an efiicient utilization of the available total throughpassage area approximately in comparison with circular throughpassage openings.

A further embodiment of quick closure mechanism or device designed according to the teachings of the present invention is illustrated in FIGURES 8, 9 and 10. This embodiment essentially differs from that shown in FIG- URES 4, 5 and 6 in that a movable plate-shaped element is located between two rigidly arranged plates. Here again, in this embodiment a seating portion 30 is secured to the flat bars 4 between the inner frame 2 and intermediate frame 3. As clearly shown in FIGURE 9 this seating portion 36 exhibits a convex dome or arched portion 30a directed towards the inner compartment I, with the remainder of such seating portion being similarly constructed as previously described, in particular wit-h lengthwise openings or slots 30b.

A seating plate 31 connects with this arched or domeshaped plate 30 and exhibits a dome or arch portion 31a curved opposite to the seating portion 30. This seating plate 31 bears with its upper and lower marginal regions, as shown in FIGURE 9, at the inside against the marginal or peripheral zone of the seating portion 30 and at the outside face against the external or outer frame 8, similar to the previously described embodiment. The seating plate 31 can be manufactured to be considerably thinner than necessary for the seating portion 30 for the same reasons which were decisive for the dimensioning of the previously described external plate 25. Between the seating plate 31 and the seating plate 30 there is arranged a membrane-like closure plate 33 formed of a plurality of parallelly extending elastic spring type flanges or webs 39. If these webs are impinged by the pressure wave or the suction wave respectively, such tend to bend through and bear against the inner surface of the respective seating portion 30 or seating plate 31, arched concave with respect to the closure plate 33, whereby they cover the slots of the relevant seat member.

According to FIGURE 10 the seating portion 30 is formed of individual webs or legs 34 which at the marginal regions are separated by intermediate members 35. The seating plate 31 is likewise composed of individual webs or legs 36 separated by intermediate members 37. at the contact locations or plane of joinder the plates 31 and 30 form a transverse slot 38 in which the individual legs or webs 39 of the closure plate 33 in each case are movably arranged and aligned with the slots 3% and 31b between the webs 34 and 36 respectively. In order to prevent binding during through bending of the webs 39 and to guarantee for a faultless bearing against the inner surface of the seat or base plate 30 and outer plate 31 respectively, the cross-section of the slot is advantageously of V-shaped configuration. A displacement of each web 39 in the lengthwise direction of the slot 38 is prevented by a respective crosspiece or web portion 40 extending transverse to the slot 38 and which engages with the relevant web 39, for which purpose the latter is provided at its ends with suitable slot means 41.

Also, in the case of the last-mentioned embodiment the plate surface and Web surfaces respectively can be coated with a preferably noncombustible dampening material, as generally indicated, at 51, in FIGURE 10. Additionally it is possible, similar to the first embodiment, to leave away the plate 31. In accordance with a further embodiment of quick closure device it is additionally possible to arrange a seating portion, similar to that of the first and second embodiments, in inclined position in the throughpassage opening which during normal ventilation operation encloses an angle with a closure plate. In this case, then, the closure plate is articulated at one side and is swingable against the seating portion and against the action of a counterforce. Naturally, also .in this case two movable closure plates can be provided which are hinged about a common pivot axis towards one another and towards the seating portion. It will also be recalled that the closure member can be formed of rigid or elastic material, depending upon requirements. Furthermore, it should be understood that individual features of one embodiment can be combined with those of another embodiment.

While there is shown and described present preferred embodiments of the invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practised within the scope of the following claims.

What is claimed is:

1. A quick closure mechanism for an air passage opening of shelters and other protective type compartments, comprising at least one movable closure means mounted in the air passage opening and movable in response to the sudden differences in air pressure appearing at opposite sides of said air passage opening, stationary seating means against which said closure means sealingly bears in the closed position of said closure means, means for mounting said movable closure means so that in the absence of said pressure dilferences it normally assumes an open position, said closure means and seating means being constructed as plate-shaped elements provided with openings, at least one of said plate-shaped elements being provided with a layer of non-combustible damping material at a surface thereof partaking in a sealing action, said openings of each said plate-shaped element being separated by uninterrupted plate portions, said plateshaped closure means and said plate-shaped seating means lying against one another in said closed position of said closure means, said openings of said closure means being offset with respect to the openings of said seating means and lying in the zone of the uninterrupted plate portions of said seating means.

2. A quick closure mechanism for an air passage opening of shelters and other protective type compartments,

comprising at least one movable closure means mounted in the air passage opening and movable in response to the sudden differences in air pressure appearing at opposite sides of said air passage opening, stationary seating means against which said closure means sealingly bears in the closed position of said closure means, said closure means and seating means being constructed as plate-shaped elements provided with openings, said openings of each said plate-shaped element being separated by uninterrupted plate portions, said plate-shaped closure means and said plate-shaped seating means lying against one another in said closed position of said closure means, said openings of said closure means being offset with respect to the openings of said seating means and lying in the zone of the uninterrupted plate portions of said seating means, further seating means disposed at the side of said movable closure means facing away from said stationary seating means, stop means located at the side of said further seating means facing away from said movable closure means for retaining said further seating means, said further seating means being provided with openings which are offset with respect to the, openings of said closure means, at least the portion of said movable closure means provided with said openings being spaced from said stationary seating means and said further seating means in the rest position of the quick closure mechanism during ventilation operation, said movable closure means being movable against said further seating means under the action of an air pressure surge emanating from internally of the shelter to such a degree that said closure means sealingly bears against said further seating means.

3. A quick closure mechanism as defined in claim 2 wherein said further seating means is movably mounted, said stop means being stationary, said mounting means incorporating means for producing a counterforce against said further seating means which during ventilation operation maintains said further seating means against said stop means and spaced from said stationary seating means, said further seating means being displaceable in the direction of said stationary seating means in the presence of an externally emanating air pressure surge and While overcoming the action of said counterforce means.

4. A quick closure mechanism as defined in claim 2 wherein said further seating means is stationary, said closure means disposed between said further seating means and said stationary seating means being of membrane-like construction, said membrane-like closure means being deflecta-ble into sealing contact with said further seating means or said stationary seating means in accord ance with the direction of an encountered air pressure surge.

5. A quick closure mechanism as defined in claim 4 wherein said closure means is formed of flexible elastic material, the surface portion of said stationary seating means facing towards said movable closure means and providing a sealing seat being provided with a concave curvature.

6. A quick closure mechanism as defined in claim 2 wherein said further seating means is also constructed as a plate-shaped element, at least one of said plate-shaped elements provided with said openings incorporating adjacently arranged and approximately similarly constructed web means.

7. A quick closure mechanism as defined in claim 2 wherein said further seating means is also constructed as a plate-shaped element, said openings of said individual plate-shaped elements being numerous and approximately uniformly divided throughout the surface of the relevant plate-shaped element appearing within the peripheral portions of such plate-shaped element, the individual openings of each plate-shaped element being maintained so large with respect to the uninterrupted plate portions separating such openings such that said uninterrupted plate portions exhibit mutual contact surfaces which are just suflicient to effect a sealing action.

8. A quick closure mechanism for an air passage opening of shelters and other protective type compartments, comprising at least one movable flexible closure means mounted in the air passage opening and movable in response to sudden differences in air pressure appearing at opposite sides of said air passage opening, at least one stationary seating means carrying said movable flexible closure means in a manner that in the absence of said pressure differences it normally assumes an open position, said stationary seating means having a concave surface portion facing said movable flexible closure means and defining a seat against which sealingly bears said movable flexibleclosure means in its closed position, said movable flexible closure means and seating means being constructed as plate-shaped elements provided with openings, said openings of each plate-shaped element being separated by uninterrupted plate portions, said plateshaped closure means and said plate-shaped seating means bearing against one another in said closed position of said closure means, said openings of said movable flexible closure means being oifset with respect to the openings of said stationary seating means and lying in the zone of the uninterrupted plate portions of said stationary seating means.

9. A quick closure mechanism as defined in claim 8, including a further stationary seating means at the opposite side of said movable flexible closure means and remote from said one stationary seating means, said further stationary seating means also having a concave surface portion facing said movable flexible closure means and defining a seat against which sealingly bears said movable flexible closure means in a further closed position, both of said stationary seating means abutting one another at respective diametrically opposed ends thereof and having means defining a support for freely carrying said movable flexible closure means for slight lifting movement of the latter in the presence of pressure differences out of said support and in a direction away from said diametrically abutting ends of said stationary seating means, to enable said movable flexible closure means to References Cited by the Examiner UNITED STATES PATENTS 1,154,962 9/1915 Bayles 137-517 X 2,000,735 5/1935 Arnold 137512.1 X 3,015,342 1/196'2 Price 137517 X 3,162,699 12/1964 Sivyer 137--5l2.1 X

MEYER PERLIN, Primary Examiner.

JOHN F. OCONNOR, Examiner. 

8. A QUICK CLOSURE MECHANISM FOR AN AIR PASSAGE OPENING OF SHELTERS AND OTHER PROTECTIVE TYPE COMPARTMENTS, COMPRISING AT LEAST ONE MOVABLE FLEXIBLE CLOSURE MEANS MOUNTED IN THE AIR PASSAGE OPENING AND MOVABLE IN RESPONSE TO SUDDEN DIFFERENCES IN AIR PRESSURE APPEARING AT OPPOSITE SIDES OF SAID AIR PASSAGE OPENING, AT LEAST ONE STATIONARY SEATING MEANS CARRYING SAID MOVABLE FLEXIBLE CLOSURE MEANS IN A MANNER THAT IN THE ABSENCE OF SAID PRESSURE DIFFERENCES IT NORMALLY ASSUMES AN OPEN POSITION, SAID STATIONARY SEATING MEANS HAVING A CONCAVE SURFACE PORTION FACING SAID MOVABLE FLEXIBLE CLOSURE MEANS AND DEFINING A SEAT AGAINST WHICH SEALINGLY BEARS SAID MOVABLE FLEXIBLE CLOSURE MEANS IN ITS CLOSED POSITION, SAID MOVABLE FLEXIBLE CLOSURE MEANS AND SEATING MEANS BEING CONSTRUCTED AS PLATE-SHAPED ELEMENTS PROVIDED WITH OPENINGS, SAID OPENINGS OF EACH PLATE-SHAPED ELEMENT BEING SEPARATED BY UNINTERRUPTED PLATE PORTIONS, SAID PLATESHAPED CLOSURE MEANS AND SAID PLATE-SHAPED SEATING MEANS BEARING AGAINST ONE ANOTHER IN SAID CLOSED POSITION OF SAID CLOSURE MEANS, SAID OPENINGS OF SAID MOVABLE FLEXIBLE CLOSURE MEANS BEING OFFSET WITH RESPECT TO THE OPENINGS OF SAID STATIONARY SEATING MEANS AND LYING IN THE ZONE OF THE UNINTERRUPTED PLATE PORTIONS OF SAID STATIONARY SEATING MEANS. 